A head mounted display (HMD) is a display device which is worn on the head or as part of a helmet, and which has a small display optic in front of one or each eye. Usually, it is necessary for a user that has an eye condition (e.g., myopia, hyperopia, presbyopia, etc.) to wear glasses when using the HMD. However, wearing the glasses and the HMD at the same time may result in discomfort of the user.